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  • Writer's pictureJonathan Stoddard

Some Of The Most Common Lawn Diseases!

Updated: Sep 22, 2021

Does your lawn have spots? No one likes a less-than-perfect yard! So, we will be discussing the topmost common lawn diseases that you need to keep an eye out for. If you can spot signs early on, you can easily combat those common turf diseases.

Q: What are the most common turfgrass diseases in homeowners lawns that I should be aware of?

A: Because turfgrass management can be complex, here are the top five lawn diseases to avoid.

All About Brown Patch Fungus (Rhizoctonia Solani)

Brown Patch Fungus image
Brown Patch Fungus image courtesy of Wikipedia

Brown patch is among the most common diseases that can infect practically any cool-season grass lawn in various parts of the country. This disease may cause problems on tall grass, Kentucky bluegrass, and perennial ryegrass when overnight temperatures begin to stay around 65 to 70 degrees Fahrenheit in early July. While it is relatively easy to spot (see the photo of brown patch symptom above), it can penetrate any turf stand and, by the time you realize it, it will have reached dangerously high levels.

Brown patch fungus can be controlled in various ways, many of which are both practical and easy to implement. The QoI family of fungicides (strobilurins) is one of the most acceptable fungicide alternatives for brown patch control. It provides up to 28 days of management and control of other diseases that may appear simultaneously.

All About Large Patch Fungus (Rhizoctonia Solani)

Large Patch Fungus image
Large Patch Fungus image courtesy of University of Florida

In the transition zone and south, a pathogen identical to the one that causes a brown patch generates huge patches on hot turfgrasses like zoysiagrass and bermudagrass. While the pathogen is the same, the symptoms of the large patch fungus are distinct from those of the brown patch in that they often appear in the spring or autumn, especially when the weather is cloudy, cold, and humid. As the name implies, significant patch symptoms start as small baseball-sized patches but can grow to reach the size of a car.

When the disease is active, the borders of the patch will have off-colored turf, while the middle of the patch will have thin existing grass or other healthy species that are not impacted by the disease. Fungicides can be utilized for controlling the disease if applied in the fall or early in the spring when the fungal disease is first noticed. Many spring treatments could be required to stop the progression of turf fungal diseases. Control can be achieved using strobilurins, SDHIs (penthiopyrad, etc.), and combination products comprising strobilurins and DMIs (azoxystrobin + propiconazole).

All About Pythium blight (Pythium aphanidermatum)

Pythium Blight image
Pythium Blight image courtesy of NC state extension

Pythium blight, a foliar disease that can quickly spread across sensitive turf stands, particularly seedlings. Pythium outbreaks are categorized as water mold. They are generally linked with poorly drained soils and damp, humid conditions in the turfgrass canopy with little drying of the turf leaves. Newly planted regions with daily irrigation can offer optimal conditions for the growth of pythium. During mornings with dew, Pythium blight signs include circular regions 1 to 3 inches in diameter and grey, water-soaked leaves and potentially white mycelium. Pythium can be controlled using fungicides (mefenoxam, for example), but they must be used before symptoms appear. Fungicides are not nearly as efficient at stopping the disease once symptoms begin.

All About Pink snow mold Fungus (Microdochium nivale)

Pink snow mold image
pink snow mold image courtesy of Wikipedia

One may assume that a disease with a name like pink snow mold would be easy to recognize. On the other hand, pink snow mold only turns pink for a short period and does not require snow to infect the lawn. Pink snow mold can grow all year in regions where the weather is cold and damp, such as the Pacific Northwest. Small circular spots with a water-soaked look around the margin are the first symptoms. White mycelium might be visible in the patch in particularly damp conditions, and the borders may be reddish pink.

Dry conditions cause the patches to turn brown and lose their pigment. While there are treatments for pink snow mold once symptoms appear, prevention is far more successful. The most effective and longest-lasting fungicides are DMI and strobilurin. As long as the weather is favorable, many applications may be required.

All About Summer patch (Magnaporthe poae) / Necrotic Ring Spot (Ophiosphaerella korrae)

summer patch fungus image
summer patch fungus image courtesy of NC state extension

Summer patch and necrotic ring patch in Kentucky bluegrass might be one of the more complex diseases to control while being less common than some of the other diseases mentioned so far. Late in the summer, the symptoms appear as circular patches of tan or brownish turf. This disease causes damage in late spring and early summer, but symptoms do not appear until the turf is stressed later in the season. Control methods are very restricted once symptoms appear. Summer patch / necrotic ring spot damage on the lawn can be minimized, if not entirely removed, by preventive fungicides. These applications should be applied in late spring, when the pathogen is active, and when soil temperatures exceed 65 degrees Fahrenheit. The most effective fungicides are strobilurins and DMI (propiconazole). Frequent irrigation to assist the lawn recover after disease symptoms are present is beneficial; however, chemical control measures are inefficient at this phase.

If you live in the Daytona Beach, Fl. area or greater Volusia County or Flagler county of Florida, Imperial Pest Prevention can help. Contact us at 386-956-9506. We offer a wide array of lawn service applications and can assist with fungal concerns on your turf.


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